Does your dual zone climate control over compensate for sunlight?

[Corey_R]

The temperatures I logged from the climatronic system are plotted here. The cabin temperature is regulated fairly well, but you can see how significantly the vent temperatures vary - a good reason not to have them pointed at your face!

I think that's what the crux of the issue is here. Whether you have the vents aimed AT you, or AROUND you. Aircon vents should really be aimed AROUND you, and VW have clearly engineered the system to be configured as such. I personally only ever put the vents directly on me if I've just jumped into the car on a hot day when it was sitting in the sun, and then move them back so they are blowing air around me once cabin temps has returned to "normal".

[pologti18t]

I think that's what the crux of the issue is here. Whether you have the vents aimed AT you, or AROUND you. Aircon vents should really be aimed AROUND you, and VW have clearly engineered the system to be configured as such. I personally only ever put the vents directly on me if I've just jumped into the car on a hot day when it was sitting in the sun, and then move them back so they are blowing air around me once cabin temps has returned to "normal".

Seems to me VW have designed the system to predict potential temperature changes and nip them in the bud before cabin temps deviate too much to what you set.

[GTICam]

That's an impressive plot "prise". Thanks for posting it. Shame it doesn't show fan speed too. Amazing how you can see the massive hyseresis in the aircon system control. No wonder, with the short coupling of the sunlight sensor on the dash to the fan speed, it overcompensates when driving into direct sunlight.

The mask I'm using inside the dash sunlight sensor cap seems to be keeping the fan speed under better control, and the cabin temps much more even.

BTW. Corey R, I tried the vents in all positions (I mostly drive with the airflow directed into the cabin, not blowing over me) and even tried the various manual vent selection positions to no avail. The Golf system works, but is just too clever for it's own good. Same deal in my book for the auto wipers. Overengineered high tech crap.

[logger]

..also be interesting to compare sensed cabin temp to true cabin temp as felt by the occupant. Good chance they differ somewhat depending on where the systems sensor is located.

[prise]

The cabin temperature sensor is located behind the dimple in the glossy black panel just below the top row of buttons on the HVAC control panel. It appears to be sensitive to a combination of the surface temperature of the materials inside the cabin (eg, an IR thermometer) and the air temperature. In this respect it is different to the previous generaton systems that measured air temperature only. That is probably why it is returning a higher reading than the set temperature (the air temp certainly didn't 'feel' like 25 deg).

I'll log fan speed and AC compressor load next time round and I think I've still got a reasonably accurate old style 'bulb' thermometer lying around to compare with the cabin air temp.

[prise]

Here's data I logged from the drive home showing the fan voltage in addition to all the temps and air-con compressor load. The cabin temperature was set to 22 deg this time. The fan voltage/speed doesn't vary a great deal and most of the control appears to be achieved by varying the compressor torque and the hot/cold air mixer flaps (not shown).

http://dl.dropbox.com/u/14542234/LOG...2010_11_16.pdf

The vehicle is parked underground during the day so the interior temperature is usually pretty OK when I start the car.

[Someone]

Yesterday I discovered that the Golf climate control AUTO button has 2 settings. It toggles between a normal fan setting and a "high blower output" setting. I reckon the latter is the default. This explains why my fan always seemed to be blowing lots of hot/cold air.

[Corey_R]

Yeah. On my MY11 R, a single press of the Auto button and it goes to the left light, which is the lower ("normal" ?) setting. Whereas, in the manual it says that a single press goes to the right light (the "high blower output" setting) and a 2nd press is required to go to normal.

So I agree, this setting will have a big influence on the way the system reacts.

[prise]

But which one is the 'normal' mode? My manual refers to them as AUTO Low and AUTO High. I tend to set mine to high with the vents pointed up and away from me. The aircon will run a bit more efficiently with more airflow through the evaporator (heat exchanger).

[GTI mk6]

Hi Guys,

Today in Sydney with 26 Degrees and Sunny I found myself having the Temp Setting at 26 degrees it would of been higher if there were more setting betting 26 and HI.

It definitely is over compensating for sunlight.

Can anyone help with where the sensors are or any other solution ?

+1
Exact same scenario and thoughts as you but in Melbourne when out cruising yesterday.
Initially turned AC off, then too hot again....ended up tilting all air vents upwards with temp. controls on 26.
Much better....and although I am used to a breeze on my face, will just need to adapt I guess